@article{ChengWollertChenetal.2023, author = {Cheng, Chi-Tsun and Wollert, J{\"o}rg and Chen, Xi and Fapojuwo, Abraham O.}, title = {Guest Editorial : Circuits and Systems for Industry X.0 Applications}, series = {IEEE Journal on Emerging and Selected Topics in Circuits and Systems}, volume = {13}, journal = {IEEE Journal on Emerging and Selected Topics in Circuits and Systems}, edition = {2}, publisher = {IEEE}, address = {New York}, issn = {2156-3357 (Print)}, doi = {10.1109/JETCAS.2023.3278843}, pages = {457 -- 460}, year = {2023}, language = {en} } @article{LuftBremenLuft2023, author = {Luft, Angela and Bremen, Sebastian and Luft, Nils}, title = {A cost/benefit and flexibility evaluation framework for additive technologies in strategic factory planning}, series = {Processes}, volume = {11}, journal = {Processes}, number = {7}, publisher = {MDPI}, address = {Basel}, issn = {2227-9717}, doi = {10.3390/pr11071968}, pages = {Artikel 1968}, year = {2023}, abstract = {There is a growing demand for more flexibility in manufacturing to counter the volatility and unpredictability of the markets and provide more individualization for customers. However, the design and implementation of flexibility within manufacturing systems are costly and only economically viable if applicable to actual demand fluctuations. To this end, companies are considering additive manufacturing (AM) to make production more flexible. This paper develops a conceptual model for the impact quantification of AM on volume and mix flexibility within production systems in the early stages of the factory-planning process. Together with the model, an application guideline is presented to help planners with the flexibility quantification and the factory design process. Following the development of the model and guideline, a case study is presented to indicate the potential impact additive technologies can have on manufacturing flexibility Within the case study, various scenarios with different production system configurations and production programs are analyzed, and the impact of the additive technologies on volume and mix flexibility is calculated. This work will allow factory planners to determine the potential impacts of AM on manufacturing flexibility in an early planning stage and design their production systems accordingly.}, language = {en} } @article{Pfaff2023, author = {Pfaff, Raphael}, title = {Braking distance prediction for vehicle consist in low-speed on-sight operation: a Monte Carlo approach}, series = {Railway Engineering Science}, volume = {31}, journal = {Railway Engineering Science}, number = {2}, publisher = {SpringerOpen}, issn = {2662-4753 (eISSN)}, doi = {10.1007/s40534-023-00303-7}, pages = {135 -- 144}, year = {2023}, abstract = {The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive (e.g. in the case of depot operations) or highly inefficient (e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for low-speed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.}, language = {en} } @article{AbbasHedwigBalcetal.2023, author = {Abbas, Karim and Hedwig, Lukas and Balc, Nicolae and Bremen, Sebastian}, title = {Advanced FFF of PEEK: Infill strategies and material characteristics for rapid tooling}, series = {Polymers}, volume = {2023}, journal = {Polymers}, number = {15}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/polym15214293}, pages = {Artikel 4293}, year = {2023}, abstract = {Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK's economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100\% solid and subjected to thermal post-treatment. This corresponds to a 20\% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15\% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70\% in tool production.}, language = {en} } @article{LuftLuftArntz2023, author = {Luft, Angela and Luft, Nils and Arntz, Kristian}, title = {A basic description logic for service-oriented architecture in factory planning and operational control in the age of industry 4.0}, series = {Applied Sciences}, volume = {2023}, journal = {Applied Sciences}, number = {13}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/app13137610}, pages = {Artikel 7610}, year = {2023}, abstract = {Manufacturing companies across multiple industries face an increasingly dynamic and unpredictable environment. This development can be seen on both the market and supply side. To respond to these challenges, manufacturing companies must implement smart manufacturing systems and become more flexible and agile. The flexibility in operational planning regarding the scheduling and sequencing of customer orders needs to be increased and new structures must be implemented in manufacturing systems' fundamental design as they constitute much of the operational flexibility available. To this end, smart and more flexible solutions for production planning and control (PPC) are developed. However, scheduling or sequencing is often only considered isolated in a predefined stable environment. Moreover, their orientation on the fundamental logic of the existing IT solutions and their applicability in a dynamic environment is limited. This paper presents a conceptual model for a task-based description logic that can be applied to factory planning, technology planning, and operational control. By using service-oriented architectures, the goal is to generate smart manufacturing systems. The logic is designed to allow for easy and automated maintenance. It is compatible with the existing resource and process allocation logic across operational and strategic factory and production planning.}, language = {en} } @article{UlmerBraunChengetal.2023, author = {Ulmer, Jessica and Braun, Carsten and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {A human factors-aware assistance system in manufacturing based on gamification and hardware modularisation}, series = {International Journal of Production Research}, journal = {International Journal of Production Research}, publisher = {Taylor \& Francis}, issn = {0020-7543 (Print)}, doi = {10.1080/00207543.2023.2166140}, year = {2023}, abstract = {Assistance systems have been widely adopted in the manufacturing sector to facilitate various processes and tasks in production environments. However, existing systems are mostly equipped with rigid functional logic and do not provide individual user experiences or adapt to their capabilities. This work integrates human factors in assistance systems by adjusting the hardware and instruction presented to the workers' cognitive and physical demands. A modular system architecture is designed accordingly, which allows a flexible component exchange according to the user and the work task. Gamification, the use of game elements in non-gaming contexts, has been further adopted in this work to provide level-based instructions and personalised feedback. The developed framework is validated by applying it to a manual workstation for industrial assembly routines.}, language = {en} } @inproceedings{ChavezBermudezWollert2022, author = {Chavez Bermudez, Victor Francisco and Wollert, J{\"o}rg}, title = {10BASE-T1L industry 4.0 smart switch for field devices based on IO-Link}, series = {2022 IEEE 18th International Conference on Factory Communication Systems (WFCS)}, booktitle = {2022 IEEE 18th International Conference on Factory Communication Systems (WFCS)}, publisher = {IEEE}, isbn = {978-1-6654-1086-1}, doi = {10.1109/WFCS53837.2022.9779176}, pages = {4 Seiten}, year = {2022}, abstract = {The recent amendment to the Ethernet physical layer known as the IEEE 802.3cg specification, allows to connect devices up to a distance of one kilometer and delivers a maximum of 60 watts of power over a twisted pair of wires. This new standard, also known as 10BASE-TIL, promises to overcome the limits of current physical layers used for field devices and bring them a step closer to Ethernet-based applications. The main advantage of 10BASE- TIL is that it can deliver power and data over the same line over a long distance, where traditional solutions (e.g., CAN, IO-Link, HART) fall short and cannot match its 10 Mbps bandwidth. Due to its recentness, IOBASE- TIL is still not integrated into field devices and it has been less than two years since silicon manufacturers released the first Ethernet-PHY chips. In this paper, we present a design proposal on how field devices could be integrated into a IOBASE-TIL smart switch that allows plug-and-play connectivity for sensors and actuators and is compliant with the Industry 4.0 vision. Instead of presenting a new field-level protocol for this work, we have decided to adopt the IO-Link specification which already includes a plug-and-play approach with features such as diagnosis and device configuration. The main objective of this work is to explore how field devices could be integrated into 10BASE-TIL Ethernet, its adaption with a well-known protocol, and its integration with Industry 4.0 technologies.}, language = {en} } @inproceedings{UlmerBraunChengetal.2022, author = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Usage of digital twins for gamification applications in manufacturing}, series = {Procedia CIRP}, volume = {107}, booktitle = {Procedia CIRP}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2022.05.044}, pages = {675 -- 680}, year = {2022}, abstract = {Gamification applications are on the rise in the manufacturing sector to customize working scenarios, offer user-specific feedback, and provide personalized learning offerings. Commonly, different sensors are integrated into work environments to track workers' actions. Game elements are selected according to the work task and users' preferences. However, implementing gamified workplaces remains challenging as different data sources must be established, evaluated, and connected. Developers often require information from several areas of the companies to offer meaningful gamification strategies for their employees. Moreover, work environments and the associated support systems are usually not flexible enough to adapt to personal needs. Digital twins are one primary possibility to create a uniform data approach that can provide semantic information to gamification applications. Frequently, several digital twins have to interact with each other to provide information about the workplace, the manufacturing process, and the knowledge of the employees. This research aims to create an overview of existing digital twin approaches for digital support systems and presents a concept to use digital twins for gamified support and training systems. The concept is based upon the Reference Architecture Industry 4.0 (RAMI 4.0) and includes information about the whole life cycle of the assets. It is applied to an existing gamified training system and evaluated in the Industry 4.0 model factory by an example of a handle mounting.}, language = {en} } @inproceedings{DannenSchindelePruemmeretal.2022, author = {Dannen, Tammo and Schindele, Benedikt and Pr{\"u}mmer, Marcel and Arntz, Kristian and Bergs, Thomas}, title = {Methodology for the self-optimizing determination of additive manufacturing process eligibility and optimization potentials in toolmaking}, series = {Procedia CIRP}, volume = {107}, booktitle = {Procedia CIRP}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2022.05.188}, pages = {1539 -- 1544}, year = {2022}, abstract = {Additive Manufacturing (AM) of metallic workpieces faces a continuously rising technological relevance and market size. Producing complex or highly strained unique workpieces is a significant field of application, making AM highly relevant for tool components. Its successful economic application requires systematic workpiece based decisions and optimizations. Considering geometric and technological requirements as well as the necessary post-processing makes deciding effortful and requires in-depth knowledge. As design is usually adjusted to established manufacturing, associated technological and strategic potentials are often neglected. To embed AM in a future proof industrial environment, software-based self-learning tools are necessary. Integrated into production planning, they enable companies to unlock the potentials of AM efficiently. This paper presents an appropriate methodology for the analysis of process-specific AM-eligibility and optimization potential, added up by concrete optimization proposals. For an integrated workpiece characterization, proven methods are enlarged by tooling-specific figures. The first stage of the approach specifies the model's initialization. A learning set of tooling components is described using the developed key figure system. Based on this, a set of applicable rules for workpiece-specific result determination is generated through clustering and expert evaluation. Within the following application stage, strategic orientation is quantified and workpieces of interest are described using the developed key figures. Subsequently, the retrieved information is used for automatically generating specific recommendations relying on the generated ruleset of stage one. Finally, actual experiences regarding the recommendations are gathered within stage three. Statistic learning transfers those to the generated ruleset leading to a continuously deepening knowledge base. This process enables a steady improvement in output quality.}, language = {en} } @article{AbbasBalcBremenetal.2022, author = {Abbas, Karim and Balc, Nicolae and Bremen, Sebastian and Skupin, Marco}, title = {Crystallization and aging behavior of polyetheretherketone PEEK within rapid tooling and rubber molding}, series = {Journal of Manufacturing and Materials Processing}, volume = {6}, journal = {Journal of Manufacturing and Materials Processing}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2504-4494}, doi = {10.3390/jmmp6050093}, pages = {1 -- 12}, year = {2022}, abstract = {In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30\% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking.}, language = {en} } @inproceedings{WeissHeslenfeldSaeweetal.2022, author = {Weiss, Christian and Heslenfeld, Jonas and Saewe, Jasmin Kathrin and Bremen, Sebastian and H{\"a}fner, Constantin Leon}, title = {Investigation on the influence of powder humidity in Laser Powder Bed Fusion (LPBF)}, series = {Procedia CIRP}, volume = {111}, booktitle = {Procedia CIRP}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2022.08.102}, pages = {115 -- 120}, year = {2022}, abstract = {In the Laser Powder Bed Fusion (LPBF) process, parts are built out of metal powder material by exposure of a laser beam. During handling operations of the powder material, several influencing factors can affect the properties of the powder material and therefore directly influence the processability during manufacturing. Contamination by moisture due to handling operations is one of the most critical aspects of powder quality. In order to investigate the influences of powder humidity on LPBF processing, four materials (AlSi10Mg, Ti6Al4V, 316L and IN718) are chosen for this study. The powder material is artificially humidified, subsequently characterized, manufactured into cubic samples in a miniaturized process chamber and analyzed for their relative density. The results indicate that the processability and reproducibility of parts made of AlSi10Mg and Ti6Al4V are susceptible to humidity, while IN718 and 316L are barely influenced.}, language = {en} } @article{PfaffEnningSutter2022, author = {Pfaff, Raphael and Enning, Manfred and Sutter, Stefan}, title = {A risk‑based approach to automatic brake tests for rail freight service: incident analysis and realisation concept}, series = {SN Applied Sciences}, volume = {4}, journal = {SN Applied Sciences}, number = {4}, publisher = {Springer}, address = {Cham}, issn = {2523-3971}, doi = {10.1007/s42452-022-05007-x}, pages = {1 -- 14}, year = {2022}, abstract = {This study reviews the practice of brake tests in freight railways, which is time consuming and not suitable to detect certain failure types. Public incident reports are analysed to derive a reasonable brake test hardware and communication architecture, which aims to provide automatic brake tests at lower cost than current solutions. The proposed solutions relies exclusively on brake pipe and brake cylinder pressure sensors, a brake release position switch as well as radio communication via standard protocols. The approach is embedded in the Wagon 4.0 concept, which is a holistic approach to a smart freight wagon. The reduction of manual processes yields a strong incentive due to high savings in manual labour and increased productivity.}, language = {en} } @article{UlmerBraunChengetal.2022, author = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Gamification of virtual reality assembly training: Effects of a combined point and level system on motivation and training results}, series = {International Journal of Human-Computer Studies}, volume = {165}, journal = {International Journal of Human-Computer Studies}, number = {Art. No. 102854}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1071-5819}, doi = {10.1016/j.ijhcs.2022.102854}, year = {2022}, abstract = {Virtual Reality (VR) offers novel possibilities for remote training regardless of the availability of the actual equipment, the presence of specialists, and the training locations. Research shows that training environments that adapt to users' preferences and performance can promote more effective learning. However, the observed results can hardly be traced back to specific adaptive measures but the whole new training approach. This study analyzes the effects of a combined point and leveling VR-based gamification system on assembly training targeting specific training outcomes and users' motivations. The Gamified-VR-Group with 26 subjects received the gamified training, and the Non-Gamified-VR-Group with 27 subjects received the alternative without gamified elements. Both groups conducted their VR training at least three times before assembling the actual structure. The study found that a level system that gradually increases the difficulty and error probability in VR can significantly lower real-world error rates, self-corrections, and support usages. According to our study, a high error occurrence at the highest training level reduced the Gamified-VR-Group's feeling of competence compared to the Non-Gamified-VR-Group, but at the same time also led to lower error probabilities in real-life. It is concluded that a level system with a variable task difficulty should be combined with carefully balanced positive and negative feedback messages. This way, better learning results, and an improved self-evaluation can be achieved while not causing significant impacts on the participants' feeling of competence.}, language = {en} } @inproceedings{EvansBraunUlmeretal.2022, author = {Evans, Benjamin and Braun, Sebastian and Ulmer, Jessica and Wollert, J{\"o}rg}, title = {AAS implementations - current problems and solutions}, series = {20th International Conference on Mechatronics - Mechatronika (ME)}, booktitle = {20th International Conference on Mechatronics - Mechatronika (ME)}, publisher = {IEEE}, isbn = {978-1-6654-1040-3}, doi = {10.1109/ME54704.2022.9982933}, pages = {6 Seiten}, year = {2022}, abstract = {The fourth industrial revolution presents a multitude of challenges for industries, one of which being the increased flexibility required of manufacturing lines as a result of increased consumer demand for individualised products. One solution to tackle this challenge is the digital twin, more specifically the standardised model of a digital twin also known as the asset administration shell. The standardisation of an industry wide communications tool is a critical step in enabling inter-company operations. This paper discusses the current state of asset administration shells, the frameworks used to host them and their problems that need to be addressed. To tackle these issues, we propose an event-based server capable of drastically reducing response times between assets and asset administration shells and a multi-agent system used for the orchestration and deployment of the shells in the field.}, language = {en} } @inproceedings{ChavezBermudezCruzCastanonRuchayetal.2022, author = {Chavez Bermudez, Victor Francisco and Cruz Castanon, Victor Fernando and Ruchay, Marco and Wollert, J{\"o}rg}, title = {Rapid prototyping framework for automation applications based on IO-Link}, series = {Tagungsband AALE 2022}, booktitle = {Tagungsband AALE 2022}, editor = {Leipzig, Hochschule f{\"u}r Technik, Wirtschaft und Kultur}, address = {Leipzig}, isbn = {978-3-910103-00-9}, doi = {10.33968/2022.28}, pages = {8 Seiten}, year = {2022}, abstract = {The development of protype applications with sensors and actuators in the automation industry requires tools that are independent of manufacturer, and are flexible enough to be modified or extended for any specific requirements. Currently, developing prototypes with industrial sensors and actuators is not straightforward. First of all, the exchange of information depends on the industrial protocol that these devices have. Second, a specific configuration and installation is done based on the hardware that is used, such as automation controllers or industrial gateways. This means that the development for a specific industrial protocol, highly depends on the hardware and the software that vendors provide. In this work we propose a rapid-prototyping framework based on Arduino to solve this problem. For this project we have focused to work with the IO-Link protocol. The framework consists of an Arduino shield that acts as the physical layer, and a software that implements the IO-Link Master protocol. The main advantage of such framework is that an application with industrial devices can be rapid-prototyped with ease as its vendor independent, open-source and can be ported easily to other Arduino compatible boards. In comparison, a typical approach requires proprietary hardware, is not easy to port to another system and is closed-source.}, language = {en} } @inproceedings{UlmerMostafaWollert2022, author = {Ulmer, Jessica and Mostafa, Youssef and Wollert, J{\"o}rg}, title = {Digital Twin Academy: From Zero to Hero through individual learning experiences}, series = {Tagungsband AALE 2022 / Herausgegeben von der Hochschule f{\"u}r Technik, Wirtschaft und Kultur Leipzig}, booktitle = {Tagungsband AALE 2022 / Herausgegeben von der Hochschule f{\"u}r Technik, Wirtschaft und Kultur Leipzig}, isbn = {978-3-910103-00-9}, doi = {10.33968/2022.33}, url = {http://nbn-resolving.de/urn:nbn:de:bsz:l189-qucosa2-776097}, pages = {1 -- 9}, year = {2022}, abstract = {Digital twins are seen as one of the key technologies of Industry 4.0. Although many research groups focus on digital twins and create meaningful outputs, the technology has not yet reached a broad application in the industry. The main reasons for this imbalance are the complexity of the topic, the lack of specialists, and the unawareness of the twin opportunities. The project "Digital Twin Academy" aims to overcome these barriers by focusing on three actions: Building a digital twin community for discussion and exchange, offering multi-stage training for various knowledge levels, and implementing realworld use cases for deeper insights and guidance. In this work, we focus on creating a flexible learning platform that allows the user to select a training path adjusted to personal knowledge and needs. Therefore, a mix of basic and advanced modules is created and expanded by individual feedback options. The usage of personas supports the selection of the appropriate modules.}, language = {en} } @inproceedings{UlmerBraunChengetal.2021, author = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Adapting Augmented Reality Systems to the users' needs using Gamification and error solving methods}, series = {Procedia CIRP}, volume = {104}, booktitle = {Procedia CIRP}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2021.11.024}, pages = {140 -- 145}, year = {2021}, abstract = {Animations of virtual items in AR support systems are typically predefined and lack interactions with dynamic physical environments. AR applications rarely consider users' preferences and do not provide customized spontaneous support under unknown situations. This research focuses on developing adaptive, error-tolerant AR systems based on directed acyclic graphs and error resolving strategies. Using this approach, users will have more freedom of choice during AR supported work, which leads to more efficient workflows. Error correction methods based on CAD models and predefined process data create individual support possibilities. The framework is implemented in the Industry 4.0 model factory at FH Aachen.}, language = {en} } @article{BraunChengDoweyetal.2021, author = {Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Performance evaluation of skill-based order-assignment in production environments with multi-agent systems}, series = {IEEE Journal of Emerging and Selected Topics in Industrial Electronics}, journal = {IEEE Journal of Emerging and Selected Topics in Industrial Electronics}, number = {Early Access}, publisher = {IEEE}, address = {New York}, issn = {2687-9735}, doi = {10.1109/JESTIE.2021.3108524}, year = {2021}, abstract = {The fourth industrial revolution introduces disruptive technologies to production environments. One of these technologies are multi-agent systems (MASs), where agents virtualize machines. However, the agent's actual performances in production environments can hardly be estimated as most research has been focusing on isolated projects and specific scenarios. We address this gap by implementing a highly connected and configurable reference model with quantifiable key performance indicators (KPIs) for production scheduling and routing in single-piece workflows. Furthermore, we propose an algorithm to optimize the search of extrema in highly connected distributed systems. The benefits, limits, and drawbacks of MASs and their performances are evaluated extensively by event-based simulations against the introduced model, which acts as a benchmark. Even though the performance of the proposed MAS is, on average, slightly lower than the reference system, the increased flexibility allows it to find new solutions and deliver improved factory-planning outcomes. Our MAS shows an emerging behavior by using flexible production techniques to correct errors and compensate for bottlenecks. This increased flexibility offers substantial improvement potential. The general model in this paper allows the transfer of the results to estimate real systems or other models.}, language = {en} } @article{EngemannCoenenDawaretal.2021, author = {Engemann, Heiko and C{\"o}nen, Patrick and Dawar, Harshal and Du, Shengzhi and Kallweit, Stephan}, title = {A robot-assisted large-scale inspection of wind turbine blades in manufacturing using an autonomous mobile manipulator}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app11199271}, pages = {1 -- 22}, year = {2021}, abstract = {Wind energy represents the dominant share of renewable energies. The rotor blades of a wind turbine are typically made from composite material, which withstands high forces during rotation. The huge dimensions of the rotor blades complicate the inspection processes in manufacturing. The automation of inspection processes has a great potential to increase the overall productivity and to create a consistent reliable database for each individual rotor blade. The focus of this paper is set on the process of rotor blade inspection automation by utilizing an autonomous mobile manipulator. The main innovations include a novel path planning strategy for zone-based navigation, which enables an intuitive right-hand or left-hand driving behavior in a shared human-robot workspace. In addition, we introduce a new method for surface orthogonal motion planning in connection with large-scale structures. An overall execution strategy controls the navigation and manipulation processes of the long-running inspection task. The implemented concepts are evaluated in simulation and applied in a real-use case including the tip of a rotor blade form.}, language = {en} } @inproceedings{SchmidtKaschEichleretal.2021, author = {Schmidt, Thomas and Kasch, Susanne and Eichler, Fabian and Thurn, Laura}, title = {Process strategies on laser-based melting of glass powder}, series = {Lasers in Manufacturing Conference 2021}, booktitle = {Lasers in Manufacturing Conference 2021}, pages = {10 Seiten}, year = {2021}, abstract = {This paper presents the laser-based powder bed fusion (L-PBF) using various glass powders (borosilicate and quartz glass). Compared to metals, these require adapted process strategies. First, the glass powders were characterized with regard to their material properties and their processability in the powder bed. This was followed by investigations of the melting behavior of the glass powders with different laser wavelengths (10.6 µm, 1070 nm). In particular, the experimental setup of a CO2 laser was adapted for the processing of glass powder. An experimental setup with integrated coaxial temperature measurement/control and an inductively heatable build platform was created. This allowed the L-PBF process to be carried out at the transformation temperature of the glasses. Furthermore, the component's material quality was analyzed on three-dimensional test specimen with regard to porosity, roughness, density and geometrical accuracy in order to evaluate the developed L-PBF parameters and to open up possible applications.}, language = {en} }